Japanese Laid-open Patent Publication No. 2002-29286 discloses a control device for an internal combustion engine wherein the control device is provided with a continuously variable transmission, which continuously changes a transmission gear ratio of an output of the engine, and executes constant speed travel control of controlling an opening of a throttle valve so that a vehicle speed becomes a predetermined set vehicle speed.
With respect to a vehicle which includes a CVT (Continuously Variable Transmission), there is a case where a hunting phenomenon of the engine rpm (at a cycle of 5 s to 7 s, with an amplitude of about 100 rpm, for example) occurs when a target output driving force is slightly changed in control for keeping speed of the vehicle such as cruise control, etc. In the vehicle with the CVT, an electronic throttle as well as a transmission gear ratio of the CVT are used to control an output driving force of the vehicle. However, the electronic throttle and the CVT have delay factors in implementation systems thereof, and also different responsiveness. For this reason, if the driving force is controlled such that it increases, there is a case where the driving force is increased by the electronic throttle and then the driving force is increased by the transmission gear ratio with a delay, which causes the driving force to be too great. Then, in turn, the control for decreasing the driving force is performed, and this is repeated. Such repeated increase and the decrease in the transmission gear ratio causes the hunting phenomenon of the engine rpm.
Therefore, an object of the disclosure is to provide a vehicle control apparatus that can reduce a hunting phenomenon in a vehicle with a CVT.